For cleaning and maintenance work on higher buildings, climbing aids, in particular ladders, are frequently provided with a securing rail or a securing cable, whereon a fall arrester is guided displaceably or in a co-running manner. The fall arrester can be connected to a harness worn by the person to be secured so that this person is secured against falling. When ascending or descending on the ladder, the fall arrester virtually necessarily follows the person to be secured. The harness worn by the person to be secured is either directly or indirectly connected via a safety lanyard to a brake actuating member for actuating a brake or a locking apparatus of the fall arrester. If the brake actuating member is subjected to a larger force in the downward direction, which is the case for example when the person to be secured falls, the fall arrester is necessarily locked on the rail or clamps the safety lanyard.